In this competitive renewal of the Ruth L. Kirschstein NRSA Institutional Research Training Grant Application, we request funds to support the research training in environmental toxicology at the University of California, Riverside. The proposed interdisciplinary research training program is built upon the solid foundation of the existing curriculum structure of the environmental toxicology graduate program. The fourteen preceptors are from the Division of Biomedical Sciences as well as the Departments of Chemistry, Biochemistry, Botany and Plant Science, Chemical and Environmental Engineering, and Environmental Sciences. They have been very actively involved with the training of pre- and postdoctoral individuals in environmental toxicology and their research projects have been well funded. The research programs of these faculty members include genetic toxicology and epigenetics (Chen, Eastmond, Song, and Wang), analytical chemistry and proteomics (Ai, Cheng, Gan, Mulchandani, and Wang), oxidative stress (Ai, Julian and Wang), and endocrine disruption and metabolism (Gill, Messaoudi, Schlenk, Sladek, and Walker). Pre-doctoral trainees will be selected from the participating Chemistry and Environmental Toxicology graduate programs. An Internal Steering Committee is established to select the trainees and to monitor the progress of the trainees, and an External Advisory Board is also named to assist the management of the training program. A total of 6 trainees per year (4 pre-doctorates plus 2 post-doctorates) are requested. The trainees will be exposed to a variety of cutting-edge technologies in nanofabrication, genomics, proteomics, etc. The request for continuing funding of this research training grant is justified by the relevance of the proposed research training to environmental health, the excellent training environment, the superb experience of the preceptors in training pre- and postdoctoral individuals, the strong institutional commitment, the diverse graduate student body at the University, as well as our success in recruiting, appointing and nurturing the success of trainees in the last funding cycle.